Cervical Cancer Prevention (PDQ®)
What is prevention?
Cancer prevention is action taken to lower the chance of getting cancer. By preventing cancer, the number of new cases of cancer in a group or population is lowered. Hopefully, this will lower the number of deaths caused by cancer.
To prevent new cancers from starting, scientists look at risk factors and protective factors. Anything that increases your chance of developing cancer is called a cancer risk factor; anything that decreases your chance of developing cancer is called a cancer protective factor.
Some risk factors for cancer can be avoided, but many cannot. For example, both smoking and inheriting certain genes are risk factors for some types of cancer, but only smoking can be avoided. Regular exercise and a healthy diet may be protective factors for some types of cancer. Avoiding risk factors and increasing protective factors may lower your risk but it does not mean that you will not get cancer.
Different ways to prevent cancer are being studied, including:
- Changing lifestyle or eating habits.
- Avoiding things known to cause cancer.
- Taking medicines to treat a precancerous condition or to keep cancer from starting.
General Information About Cervical Cancer
Cervical cancer is a disease in which malignant (cancer) cells form in the cervix.Anatomy of the female reproductive system. The organs in the female reproductive system include the uterus, ovaries, fallopian tubes, cervix, and vagina. The uterus has a muscular outer layer called the myometrium and an inner lining called the endometrium.
Cervical cancer usually develops slowly over time. Before cancer appears in the cervix, the cells of the cervix go through a series of changes in which cells that are not normal begin to appear in the cervical tissue. When cells change from being normal cells to abnormal cells, it is called dysplasia. Depending on the number of abnormal cells, dysplasia may go away without treatment. The more abnormal cells there are, the less likely they are to go away. Dysplasia that is not treated may turn into cancer, over time. The cancer cells grow and spread through the cervix. It can take many years for dysplasia to turn into cancer.
See the following PDQ summaries for more information about cervical cancer:
Screening for cervical cancer using the Pap test has decreased the number of deaths from cervical cancer.
Cervical Cancer Prevention
Avoiding risk factors and increasing protective factors may help prevent cancer.
Avoiding cancer risk factors may help prevent certain cancers. Risk factors include smoking, being overweight, and not getting enough exercise. Increasing protective factors such as quitting smoking, eating a healthy diet, and exercising may also help prevent some cancers. Talk to your doctor or other health care professional about how you might lower your risk of cancer.
The following risk factors increase the risk of cervical cancer:
The most common cause of cervical cancer is infection of the cervix with human papillomavirus (HPV). There are more than 80 types of human papillomavirus. About 30 types can infect the cervix and about half of them have been linked to cervical cancer. HPV infection is common but only a very small number of women infected with HPV develop cervical cancer.
HPV infections that cause cervical cancer are spread mainly through sexual contact. Women who become sexually active at a young age and who have many sexual partners are at a greater risk of HPV infection and developing cervical cancer.
Smoking cigarettes and breathing in secondhand smoke increase the risk of cervical cancer. The risk increases with the number of cigarettes smoked per day and the younger the age when smoking began. Among women infected with HPV, cervical dysplasia and invasive cancer occur 2 to 3 times more often in current and former smokers.
Being exposed to diethylstilbestrol (DES) while in the mother's womb increases the risk of cervical dysplasia and cervical cancer. Between 1940 and 1971, the drug DES was given to some pregnant women in the United States to prevent miscarriage (premature birth of a fetus that cannot survive) and premature labor.
The following risk factors may increase the risk of cervical cancer:
High number of full-term pregnancies
Women who have had 7 or more full-term pregnancies may have an increased risk of cervical cancer.
Long-term use of oral contraceptives
Women who have used oral contraceptives ("the Pill") for 5 years or more have a greater risk of cervical cancer than women who have never used oral contraceptives. The risk is higher after 10 years of use.
The following protective factors may decrease the risk of cervical cancer:
Preventing HPV infection
HPV may be prevented by the following:
- Avoiding sexual activity: HPV infection of the cervix is the most common cause of cervical cancer. Avoiding sexual activity decreases the risk of HPV infection.
- Using barrier protection or spermicidal gels: Some methods used to prevent sexually transmitted diseases (STDs) decrease the risk of HPV infection. The use of barrier methods of birth control (such as a condom or gel that kills sperm) help protect against HPV infection.
- Getting an HPV Vaccine: Two HPV vaccines have been approved by the U.S. Food and Drug Administration (FDA). The HPV vaccines have been shown to prevent infection with the two types of HPV that cause most cervical cancers. The vaccines protect against infection with these types of HPV for 6 to 8 years. It is not known if the protection lasts longer. The vaccines do not protect women who are already infected with HPV.
Regular pelvic exams and Pap tests help find abnormal cells in the cervix before cancer develops. However, test and procedures that may be used after an abnormal pelvic exam or Pap test result have risks. For example, the treatment of low-grade lesions may affect a woman's ability to become pregnant or carry a baby to full term. In women younger than 25 years, screening with the Pap test has more risks than benefits. Screening with the Pap test is not helpful in women older than 60 years who have had recent negative Pap tests. (See the PDQ summary on Cervical Cancer Screening for more information.)
The effect of diet on cervical cancer risk is not known.
Cancer prevention clinical trials are used to study ways to prevent cancer.
Cancer prevention clinical trials are used to study ways to lower the risk of developing certain types of cancer. Some cancer prevention trials are conducted with healthy people who have not had cancer but who have an increased risk for cancer. Other prevention trials are conducted with people who have had cancer and are trying to prevent another cancer of the same type or to lower their chance of developing a new type of cancer. Other trials are done with healthy volunteers who are not known to have any risk factors for cancer.
The purpose of some cancer prevention clinical trials is to find out whether actions people take can prevent cancer. These may include eating fruits and vegetables, exercising, quitting smoking, or taking certain medicines, vitamins, minerals, or food supplements.
New ways to prevent cervical cancer are being studied in clinical trials.
Clinical trials are taking place in many parts of the country. Information about clinical trials can be found in the Clinical Trials section of the NCI Web site. Check NCI's list of cancer clinical trials for cervical cancer prevention trials that are now accepting patients.